Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/1097#discussion_r42650529
--- Diff:
flink-java/src/main/java/org/apache/flink/api/java/utils/RequiredParameter.java
---
@@ -0,0 +1,149 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.api.java.utils;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Facility to manage required parameters in user defined functions.
+ */
+public class RequiredParameter {
+
+ private static final String HELP_TEXT_PARAM_DELIMITER = "\t";
+ private static final String HELP_TEXT_LINE_DELIMITER = "\n";
+
+ private HashMap<String, Option> data;
+
+ public RequiredParameter() {
+ this.data = new HashMap<>();
+ }
+
+ public void add(Option option) throws RequiredParameterException {
+ if (!this.data.containsKey(option.getName())) {
+ this.data.put(option.getName(), option);
+ } else {
+ throw new RequiredParameterException("Option with
passed key already exists. " + option.getName());
+ }
+ }
+
+ /**
+ * Check if all parameters defined as required have been supplied.
+ *
+ * @param parameterTool - parameters supplied by user.
+ */
+ public void check(ParameterTool parameterTool) throws
RequiredParameterException {
+ for (Option o : data.values()) {
+ String key = o.getName();
+ String shortKey = o.getAlt();
+
+ boolean longKeyUndefined = keyIsUndefined(key,
parameterTool.data);
+ boolean shortKeyUndefined = keyIsUndefined(shortKey,
parameterTool.data);
+ // check if the ParameterTool contains a value for
either the full or short key (if short key is defined)
+ if (longKeyUndefined && shortKeyUndefined) {
+ throw new RequiredParameterException("Required
parameter " + key + " is not present.");
+ }
+
+ // check if the ParameterTool does not contain values
for both full and short key (if short key is defined)
+ if (parameterTool.data.containsKey(key) &&
parameterTool.data.containsKey(shortKey)) {
+ throw new RequiredParameterException("Required
parameter " + key +
+ " is defined twice: on short
and long version.");
+ }
+
+ if (!shortKeyUndefined) {
+ parameterTool.data.put(key,
parameterTool.data.get(shortKey));
+ parameterTool.data.remove(shortKey);
+ }
+
+ // key is defined and has value, now check if it
adheres to the type specified.
+ if (o.hasType() &&
!o.isCastableToDefinedType(parameterTool.data.get(key))) {
+ throw new RequiredParameterException("Parameter
" + key + " cannot be cast to the specified type.");
+ }
+ }
+ }
+
+ /**
+ * Check if all parameters defined as required have been supplied. If
not use the default values
+ * which have been supplied. If no default value is supplied for a
missing parameter, an exception is thrown.
+ *
+ * @param parameterTool - parameters supplied by the user.
+ */
+ public void checkAndPopulate(ParameterTool parameterTool) throws
RequiredParameterException {
+ for (Option o : data.values()) {
--- End diff --
Shouldn't `checkAndPopulate` do what `check` is doing and a bit more
(populating)?
Actually, I am a bit confused about the purpose of having two separate
methods.
Is it possible to merge both into a single method and call it for example
`applyTo`?
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